1. Field of the Invention
This invention relates to low formaldehyde durable press finishes.
2. Description of the Prior Art
Carbamate based finishing agents are used in the textile industry for producing durable press fabrics which require high degrees of durability of finish and white fastness. Such finishes are relatively resistant to acidic and alkaline hydrolysis and therefore the finished fabrics have a more durable smooth-drying appearance than fabrics finished with other traditionally used finishing agents such as dimethyloldihydroxyethyleneurea (DMDHEU) or dimethylolethyleneurea (DMEU).
Two major deterrents to more widespread use of carbamate based agents are (1) high free formaldehyde content of solutions of the reagent and (2) high formaldehyde release characteristics of the dried or sensitized fabrics that have been treated with the agent and of the nonwashed, cured fabric (Reid et al., American Dyestuff Reporter, Vol. 59, No. 5, p. 26, June 1970). For economic reasons, finished fabrics are rarely washed at the finishing plant prior to shipment to the garment manufacturer, retailer, or consumer. Hence, workers and users of these nonwashed carbamate-finished fabrics may be exposed to high levels of free formaldehyde and formaldehyde release.
Previously, some of these high formaldehyde release levels were lowered by reducing the ratio of formaldehyde to carbamate from greater than 2:1 to 2:1 or less in reagent preparation, and by addition of formaldehyde scavengers to the crosslinking agent solution (Frick and Reinhardt, American Dyestuff Reporter, Vol. 56, No. 9, p. 41, April 1976; U. S. Pat. Nos. 3,597,380; 3,749,751; 3,723,377). These remedial measures lowered formaldehyde release in finished fabrics to a level lower than that from fabric finished with a carbamate reactant prepared from more than 2 moles of formaldehyde per mole of carbamate, but higher than that from a finish from currently used DMDHEU reactant (Wayland et al., Textile Research Journal, Vol. 51, No. 4, p. 302, April 1981).
Two other means of producing low formaldehyde release carbamate finishes are: inclusion of a glycol in the finishing bath (Andrews et al., Textile Chemist and Colorist, Vo. 12, No. 11, p. 287, November 1980); and etherification of hydroxymethylated carbamates prior to application to fabric (Andrews and Reinhardt, U.S. Pat. No. 4,488,878). However, these procedures do not remove the formaldehyde and produce high levels of free or releasable formaldehyde from both treatment solution and dried but not cured fabrics.